improve logging output for async and sync migrate functions

[BentEngbers]

The previous log messages included applied_migrations.iter().map(ToString::to_string), which use the debug implementation for displaying the applied migrations. I have replaced them with let migrations_display = applied_migrations .iter() .map(ToString::to_string) .collect::<Vec<String>>() .join("\n");.

Additionally, for easier debugging of long-running migrations (when not in batch mode), a log message is now added before and after each migration. These messages are aligned with a \t:

[2025-04-16T09:27:40Z INFO  refinery_core::traits::sync] applying migration:     V1__foo ...
[2025-04-16T09:27:40Z INFO  refinery_core::traits::sync] applied migration:      V1__foo writing state to db.
[2025-04-16T09:27:40Z INFO  refinery_core::traits::sync] applying migration:     V2__bar ...
[2025-04-16T09:27:40Z INFO  refinery_core::traits::sync] applied migration:      V2__bar state to db.